Hydraulic engine-starting device



R. A. GALLA-NT 2,847,984

4 Sheets-Sheet 1 IN VENT 0R.

A ATTORNEY Aug. 19, 195s HYDRAULIC ENGINE-STARTING DEVICE Filed NOV. 7, 1955 Aug. 19, 1958 R. A. GALLANT HYDRAULIC ENGINE-STARTING DEVICE 4 Sheets-Sheet 2 Filed NOV. 7, 41955 f y PW ATTO RN FV Aug. 19, 1958 R. A. ALLANT v 2,847,984 HYDRAULIC ENGINESTARTING DEVICE* I Filed Nov. 7, 1955` l4 sheets-sheet s INVENTOR ATTO EY Allg- 19, 1958 R. A. GALLANT 2,847,984

HYDRAULIC ENGINE-STARTING DEVICE Filed Nov. 7, 1955 4 Sheets-Sheet 4 ATTORNEY United States Patent C 2,847,984 HYDRAULIC ENGINE-STARTING DEVICE Raymond A. Gallant, `Royal Oak, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application November7, 1955, Serial No. 545,348

Claims. (Cl. 12S-179) This invention relates generally to a power-transmitting mechanism; more particularly to a tiuid motor of the rotating-cylinder type; and, with regard to certain more specific features, to an engine-starting device comprising such a lluid motor and a starting-drive mechanism.

Hydraulic motors of the type to which the invention has particular application include a rotating cylinder` barrel having a plurality of cylinder bores formed longitudinally thereof. A piston is reciprocably mounted in each cylinder bore and bears at one end against a rotatably mounted cam member, the axis of which is inclined to and intersects the rotational axis of the cylinder barrel. The cylinder barrel rotates in endwise thrust engagement with a valve member or plate having fluid inlet and exhaust ports therein thereby controlling sequential admission and discharge of pressurized iluid to and from the several cylinder bores. In such motors, the cooperative action of the fluid pressure and of the cam acting on the several pistons causes the reciprocation of the pistons within the cylinder and this reciprocation is translated into rotation of the cylinder barrel. Such motors may be used with fluid over a wide range ofv pressures and are capable of delivering relatively high torques and rotational speeds.

ln such motors, the reactions occurring between the ends of the several pistons and the inclined cam member, in addition to effecting the rotation of the cylinder barrel, tend to cock the pistons within their respective bores. This in turn tends `to cock the cylinder barrel relative to its mounting on a drive shaft and relative to the Valve plate. These reactions also result in transverse deilective loading of the drive shaft. These resultant effects tend to decrease the performance of the motoras set forth below, and vary lin magnitude in .accordance with the rotative speed and torque loading of the motor since the reactions occurring vrbetween the ends of the several pistons and the inclined vearn plate are dependent upon the thrust loadings of the individual pistons.

In conventional motors of this type, the transverse loading of the drive shaft results in deflection of the drive shaft and in transverse displacement of the cylinder barrel relative to their normal common rotative axes thereby introducing dynamic unbalance with a consequential increase in the vibratory level of the motor and a reduction in the operative life of the bearings journaling the drive shaft. The transverse displacement of the cylinder barrel relative to the valve plate may also result in the reduction of the effective areas of the port openings thereby throttling the pressurized-Huid to and from the cylinder bores; and where the operative application of the motor requires constantly changing speed and load conditions as in hydraulic enginestarter applications, the consequential continuous changing in the transverse displacement of the cylinder barrel results in excessive wear between the mating valve faces of the cylinder barrel and valve plate.

`Cooking of the cylinder barrel with respect to the valve plate in conventional motors of this type permits performance-reducing leakage of the pressuriged iluid be- 2,847,984 Patented Aug. 19, 1958 ICC tween the mating faces of the cylinder barrel and of the valve plate; and under extreme load conditions approaching locked torque, may even provide a direct fluid connection between the inlet and outlet ports ofthe valve plate. Such leakage of pressurized hydraulic uid between the valve plate and the valve face of the cylinder barrel reduces the available torque, the maximum speed, and the acceleration response of the motor and also re'ducesthe effective period of operation that the motor Ycan be utilized for a given amount of pressurized fluid. Such cooking of the cylinder barrel relative to the valve plate alsotends to reduce or cut the lubricating film of leakage fluid between the mating surfaces of the cylinder barrel and valve plate with consequential increases inthe frictional loadings therebetween. These increased frictional loadings, and particularly where metal-to-metal contact results, reduce the efficiency of the motor and result in excessive and uneven wear therebetween which in time results in still further performance-reducing leakage.

To limit the detrimental cocking of the cylinder barrel with respect to the valve plate in such motors, it is conventional to provide a driving connection permitting limited universal action between the cylinder barrel and the drive shaft and to interpose a spring between the shaft and the cylinder to exert an axial thrust on the cylinder barrel. The axial force exerted by the spring tends to maintain the cylinder barrel in sealing engagement with the valve plate and thereby resists the cooking tendency of the cylinder barrel. However, there are -a number of disadvantages inherent in such a drive connection between the cylinder barrel and its drive shaft. The provision for limited universal action between the ycylinder barrel and the shaft whichrenders the spring effective to resist the cocking tendency applied to the cylinder barrel `also permits somewhat greater deflection of the drive shaft and consequentially increases the detrimental results stemming from such deection as discussed above. Since the aforementioned reactions and the performance-decreasing effects therefrom are of necessarily greater magnitude during the starting phase of motor operation than when the motor is operating at running torque and speed due to the relative torques and thrusts involved, the rate of the spring must necessarily be a compromise, The axial thrust exerted by the spring must be sufficient to prevent excessive leakage across the valve plate when the motor is started under load. However, the axial thrust ofthe spring Vin excess of that requiredl to prevent excessive cooking of the cylinder barrel at running torques and speeds results in unnecessary frictional loss -and wear between the valve faces under such motor operative conditions; the frictional loss and wear occurring at the mating valve faces being substantially proportional to the thrust exerted by the spring.

Some prior art motors of this type alsojournal the cylinder barrel in the motor housing to limit the cocking and transverse displacement of thecylinder barrel. The bearings utilized for this purpose have been ofboth the plain and antifriction types.` However, in practice, such motors lhave not proven too satisfactory; the cooking of the cylinder barrel within the bearings tending to increase the frictional drag on the barrel and, in some instances, resulting in scoring of the barrel and the bearings.

In applications of a hydraulic motor of the aforementioned type where the motor will be subjected to repeated starting and rapid acceleration under load, it

is extremely desirable `that the performance-reducing leakage, frictional loads, and wear occurring between the cylinder barrel and the valve plate be held to a minimum under all motor operative conditions. -This is particularly true in hydraulic engine started systems where the starter motor is normally energized for relatively short periods of time since the supply of pressurized E? fluid is generally limited to that contained in a charged pressure accumulator or reservoir and the engine-starting characteristics are generally dependent upon the torque, speed, and the acceleration response of the starter motor.

It is a principal object of the invention to provide a hydraulic fluid motor of the aforementioned type with means operative to resist cooking and lateral displacement of the cylinder barrel.

Another object of the invention is to provide a iuid motor of the aforementioned type with means operative to provide sealing engagement between the cylinder barrel and the valve plate irrespective of the cocking of the cylinder barrel relative to its normal axis of rotation.

Another object of the invention -is to provide a hydraulic starter device with a control valve assembly operable to first supply a limited quantity of pressurized uid to the hydraulic motor to insure driving engagement between the starter drive mechanism and the engine and to subsequently deliver pressurized fluid to the motor in suticient quantities to achieve enginestarting speeds and being operative to close automatically in response to starting of the engine.

Also among the several objects of the invention is to provide an improved hydraulic iluid motor. of the aforementioned type which is of simple design and relatively economical to manufacture; which is physically interchangeable with electrical starter motors in existing engine-starting installations; and which is adapted to produce substantially higher values of torque, acceleration, and speed than provided by existing electrical and hydraulic motors of comparable size.

In the main, the foregoing objects are accomplished in accordance with the invention by providing a hydraulic starter drive device including a hydraulic motor having a cylinder barrel rotatably journaled adjacent' each end in a plain bearing having fluid means associated therewith operative to prevent cooking and lateral displacement of the cylinder barrel relative to its normal axis, and having` a secondary valve plate interposed between the cylinder barrel and the stationary valve plate; the secondary valve plate being carried by the cylinder barrel and having ports therein registering with the bores of the cylinder barrel and sealed relative thereto by resilient means tending to bias the secondary plate into sealing engagement with the stationary valve plate; an overrunning clutch started drive mechanism adapted to be driven by the hydraulic motor; and a combined motor control valve and starter drive lever mechanism adapted in the same movement to rst engage a starter pinion i gear with an engine ring gear and to subsequently open a pilot valve for supplying limited pressurized fluid to the motor to effect a slow rotation thereof insuring engagement of the starter gear with the engine ring gear and for subsequently causing the opening of a main valve to admit pressurized iluid to the motor in suicient quantity to achieve engine-starting speed, and the main valve being operative to close in response to the starting of the engine.

The foregoing and other objects, advantages and features of the invention will become apparent from the following detailed description of several preferred embodiments thereof in which reference is made to the attached drawings, in which:

Figures l and la are longitudinal sectional views taken substantially on the line 1-1 of Figure 2 and show;

mating portions of a hydraulic engine-starting device embodying the invention;

Figure 2 is a sectional view taken substantially on the line 2-2 of Figure l;

Figure 3 is a transverse sectional view taken substantially on the line 3-3 of Figure 1;

Figure 4 is a sectional view taken substantially on the line 4-4 of Figure 1;

Figure 5 is a sectional view similar to a portion of Figure 1 showing a modified form of the invention; and

Figure 6 is a sectional view similar to a portion of Figure l and showing a second modified form of the invention.

Referring more particularly to the drawings, Figures 1 and 2 show a hydraulic engine-starting device comprising a casing 8, a rotary cylinder motor 9, and an overrunning clutch starter drive mechanism 10. The casing 8 includes a cap member 11, an annular bearing support member 12, a cylindrical housing member 13, a valve or porting plate 14, and a starter drive casing 15. The cap member 11, the housing member 13, and the valve plate 14 are sealed relative to each other by suitable gaskets 16, 17, and 18, and form a chamber 19 for the hydraulic motor 9. The porting plate 14 and the starter drive casing 1S similarly form a chamber 20 for the starter drive mechanism 10. The various components of the casing 8 may be .assembled by any suitable means to provide adjustability of mounting for adapting the starter mechanism to various engines and for replacement of electric motors in existing engine-starting installations. However, in the preferred embodiment, as shown by Figures l and 2, the annular member 12 is nonrotatably retained at one end of the cylindrical housing member 13 by a snap ring and a set screw as indicated at 21 and 22, respectively, and the cap member 11 is secured thereto by a plurality of equally spaced bolts 23. The valve plate member 14 is secured to the opposite end of the cylindrical housing member 13 by six equally spaced bolts 24, as shown in Figure 4, extending therethrough and is secured to the casing 15 by six similarly spaced bolts 25 which are offset slightly from the bolts 24. The casing 15 is provided with a laterally extending flange for mounting the starting device on the engine.

The starter motor 9 includes a drive shaft 26 which is journaled at vone end in a ball bearing assembly 27 carried by the annular member 12 and at its opposite end, in a plain bearing carried by the starter drive casing 15, The shaft is also journaled intermediate its ends by a bearing carried by the valve plate. A shaft seal carried by the valve plate seals the shaft with respect to the valve plate.

A cylinder barrel 29 is slidably mounted on the shaft within the motor chamber 19 by straight splines, as shown, and is rotatably supported adjacent its ends by spaced uid pressure bearings 28 carried by the cylindrical housing member 13; the fluid pressure bearings 28 being operative to prevent lateral displacement and cocking of the cylinder barrel as discussed in greater detail below. The cylinder barrel has a plurality of cylinder bores 30 extending axially thereof from its end opposite the valve plate 14. The axes of these bores are parallel to and equally spaced from the common rotative axis of the shaft 26 and the cylinder barrel 29. Each cylinder bore terminates in a port 31 of smaller dimension opening to the end surface of the cylinder barrel adjacent the valve plate 14. A secondary valve plate 32 is interposed between the cylinder barrel 29 and the valve plate 14. This secondary valve plate has a plurality of ports 33 formed therein and is nonrotatably dowelled to the cylinder barrel to maintain the ports 33 in alignment with the cylinder barrel ports 31. Resilient O-ring seals 34 are interposed between the secondary valve plate and the mating surface of the cylinder barrel in annular grooves formed radially outwardly of each of the ports 31 in the port end of the cylinder barrel. A spring 3S interposed between snap rings carried by the cylinder barrel and the shaft biases the cylinder barrel toward the valve plate 14. This biasing action serves to compress the 0-ring seals 34 between the cylinder barrel and the secondary valve plate and carries the secondary valve plate into lluid-pressure-sealing contact with the mating surface of the valve plate, The biasing thrust exerted on the shaft by the spring 35 is absorbed by the bearing assembly 27.

A piston 36 is reciprocably mounted in the open end of each of the cylinder bores. These pistons are in the form of relatively thin-walled cylinders which are closed at their ends remote from the ports 31. The closed ends of the pistons are externally rounded on a radius slightly less than the diameter of the piston about a center lying on the axis of the piston. These rounded ends of the pistons normally project from their respective cylinder bores and engage an inclined cam ring or surface provided by an adjacent race 38 of a ball bearing assembly 39. The axis of the ball bearing assembly 39 is inclined to and intersects the axis of the drive shaft 26 substantially at a point lying in the plane of the cam surface of the cam ring 38. The ball bearing assembly 39 is supported in this inclined position by an annular member 40 which is carried by the cylindrical housing member 13 and abuts the bearing support member 12. The member 40 is secured against rotation relative to the bearing support member 12 and therefore with respect to the cylindrical member 13 by the pin 41.

As the cylinder barrel is rotated relative to the valve plate, the ports 31 and 33 register alternately With a fluid pressure inlet port 42 and an outlet port 43 in the valve plate thereby sequentially introducing and discharging pressurized fluid from their respective cylinder bores to effect the driving rotation of the cylinder barrel by the cooperative action of the pistons and the inclined cam ring. Both the inlet port and the outlet port are in the form of arcuate grooves opening on the motor chamber 19 at a radius common to the ports 33 about the axis of the shaft 26 and subtending equal arcs symmetrically of a common diametrical plane. As conventional in motors of Athis type, the valve plate is provided with an annular recess or groove 44 outwardly of the ports and with a counterbore 45, both of which are coaxial with the shaft 26 and serve to limit the surface areas of the valve plate and rotary cylinder barrel in lbearing engagement so that the biasing effect of leakage pressure acting between the cylinder barrel and the valve plate substantially counterbalances the fluid back pressures acting on the ends of the piston bores which bias the cylinder barrel toward the valve plate.

The arcuate outlet port 43 communicates intermediate its ends with a discharge passage or bore 47 which extends radially outwardly of the valve plate and is connectable to a uid reservoir, not shown, by suitable piping, also not shown. The arcuate pressure inlet port 42 communicates with a radially extendinginlet passage or bore 48 which, in turn, communicates through a fitting 49 with an outlet chamber 50 of a control valve 51 which is adapted to control the supply of pressurized uid to the motor from a suitable pressure source, not shown. It will be noted that the pressure inlet passage 48 is diametrically opposite to and of somewhat smaller dimension than the discharge passage 47.

As best seen in Figure 3, both of the fluid pressure bearings 28 are provided with three equi-angularly spaced inwardly facing grooves 52. These grooves are connected through ports 53 and passages 54 and 55, which extend longitudinally of the cylindrical housing member 13, to an annular passage 57 formed between an annular groove in the valve plate member and the cylindrical housing member 13. The annular passage 57 is intermediate the gaskets 17 and 18 and is connected to the pressure inlet port 42 by one or more passages 58 formed in the valve plate. The fluid thus supplied to the grooves 52 serves to lubricate the bearing surfaces of the cylinder barrel and the bearings Z8. The running clearances between the fluid pressure bearings and the cylinder barrel are such that the relatively highly pressurized fluid supplied to the equally spaced grooves 52 also resists any cocking or lateral displacement of the cylinder barrel and tends to maintain it centered within the bearings. Should the cylinder barrel tend to move off center in one direction, the increased clearance between the opposite side of the barrel and the bearing Will decrease the effective fluid pressure applied to that side of the piston. Conversely, the effective fluid pressures acting on the cylinder barrel will be increased where the clearances between the cylinder barrel and the bearing are decreasing. The resultant dilferential in uid pressures acting on the cylinder barrel will consequently cause the cylinder barrel to again center within the bearings.

By rotatably supporting the cylinder barrel 29 within the motor housing in accordance with this aspect of the invention, detrimental cocking of the cylinder barrel and dellection of the drive shaft are prevented. This .permits the use of a straight spline connection of relatively close tolerance between the drive shaft and the barrel thereby reducing impacting, torsional Vibration, and fatigue problems inherent in such splined connections in conventional motors of this type. Since the fluid pressure bearings prevent cooking and displacement of the cylinder barrel, the thrust exerted by the spring 35 need be no more than suicient to maintain the cylinder barrel in sealing engagement with the valve plate under all motor operative conditions. Consequently, elfective sealing between the cylinder barrel and the valve plate can be achieved under low-speed, high-torque conditions without excessive thrust between the bearing surfaces and without excessive friction and wear which would result therefrom under normal running speed and torque conditions. It has thus been found from comparative test data that motors constructed in accordance with the invention are capable of developing substantially greater rotational speeds, faster rates of acceleration, higher torques, and consequentially of greater work output per unit ofrpressurized fluid under identical operative conditions than similar commercially available hydraulic motors of comparable size and displacement.

The control valve assembly 51 includes a main valve which is operably controlled by a pilot valve and pressure differentials created by the load demands on the motor. As seen in Figure la, the control valve assembly 5l comprises a valve body 62 having a bore 63 therein terminating in a frusto-conical valve seat 64 having an included angle of 60 degrees and opening on the valve r outlet chamber 50. The bore 63 is undercut adjacent the valve seat to form a valve inlet chamber 65 which communicates with the pressure source through a laterally extending passage 66 and suitable piping, not shown. A main valve spindle 67 is reciprocably mounted in the bore 63. The inner end of the valve spindle 67 is tapered to cooperate with the valve seat 64 to control the ow of fluid from the valve inlet to the outlet chamber. The outer end of the valve spindle projects through a cover plate 68 suitably secured to the valve body. The outer end of the bore 63 is counterbored to receive an annular boss 69 projecting inwardly from the cover plate. Two O-ring seals 70 and 70 carried by the boss 69 seal the cover plate with respect to the counterbore and valve spindle. The valve spindle 67 is provided with a plurality of longitudinally extending grooves 71 which serve to interconnect the valve inlet chamber 65 with the counterbore. These grooves terminate at a shoulder 72 formed on the valve spindle by a reduced diameter section adjacent the end of the counterbore and a spring 73 interposed between the cover plate and the shoulder 72 tends to bias the valve spindle 67 against the valve seat 64. A second shoulder 72 formed on the valve spindle is adapted to abut the boss on the cover plate and acts as a stop limiting the opening of the spindle with respect to the valve seat 64.

The pilot valve comprises a small bore 74 extending p longitudinally of the valve body from the opposite end on an axis offset from but parallel to the axis of the main valve bore 63. The bore 74 terminates in a tapered seat 75 opening on the valve inlet chamber 65. The end ofthe bore 74 adjacent the valve seat is connected to the valve outlet chamber 50 by a laterally extending passage 76. A needle valve spindle 77 is reciprocably mounted at its inner end within the bore 74 and terminates in a tapered portion cooperating with the tapered seat 75 to control fluid ow from the valve inlet chamber to the outlet chamber. The valve end of the spindle 77 is sealed with respect to the valve body by an O-ring 78 which is retained in place, as shown, by a threaded thimble 79. The outer end of the valve spindle 77 is reciprocably mounted within a hole formed in a bracket 80 which is mounted on the end of the valve body. Intermediate its mounting in the bracket 80 and the thimble 79, the pilot valve spindle carries a laterally extending pin 81 which is adapted to engage the end walls of a slot 82 formed in the upper arm of a pilot valve actuating lever 83. The pilot valve actuating lever 83 is pivotally mounted at 84 on the bracket 80 and a spring 85 interposed between the valve body and the upper end of the lever 83 biases the lever in a valve-closing direction. .The slot 82 is formed in the upper arm of the lever 83 intermediate its pivotal connection 84 and its connection with the spring 85 and provides a lost motion actuating connection with the valvespindle-carried pin 81.

The biasing action of the spring 8S maintains the lower arm of the actuating lever 83 in thrust engagement with the rounded toe 86 of a cam member 87 carried by a starter drive actuating lever assembly 88. The lever assembly 88 includes a lever member 89 which is mounted intermediate its ends by a pivot member 90 mounted in the starter drive casing adjacent the motor end. The upper end of the lever member 89 carries the cam member 87 which, in turn, carries an operating lever or handle 91. The lever member 89 and the handle 91 are secured to the cam member by suitable means such as the pins indicated at 92. The lower arm of the lever member 89 is bifurcated to provide two lever arms 93 having laterally extending end portions which are adapted to engage and shift the starter drive mechanism to its drive position.

The starter drive mechanism preferably includes an over-running clutch assembly 94 of a roller or ball bearing type having an input sleeve 95 which is slidably mounted on the motor drive shaft 26 by splines as indicated at 96. A collar 97 carried by the input sleeve 95 has an outwardly opening groove therein rotatably mounting a second collar 98. The collar 98 is also provided With an outwardly facing groove which engages the laterally extending end portions of the bifurcated lever arms 93. A clutch output sleeve 99 slidably embraces the motor drive shaft 26 and is externally splined as indicated at 100. The splines 100 drivingly and slidably mount a starter pinion 101 which is adapted to be selectively shifted axially by the clutch assembly into engagement with a flywheel ring gear 102 of an internal combustion engine; the ring gear being shown in broken lines in Figure 1. A helical compression spring 103 spacedly embraces the sleeve 99 and is seated at one end against a laterally extending annular shoulder formed on the sleeve adjacent the lclutch end. The opposite end of the spring is seated against the drive pinion 101 which is retained on the sleeve against the biasing action of the spring by a snap ring assembly 104.

As seen in Figure l, the starter drive mechanism 10 and the control valve 51 are shown in their positions as normally maintained by the biasing action of the spring 85. When it is desired to actuate the starting device, the starter drive actuating lever assembly 88 is rotated in a counter-clockwise direction, as seen in Figure l. This movement simultaneously carries the starter drive mechanism 10 to the right and through the cam member 87 initiates a clockwise rotation of the `pilot valve actuating lever t alignment and engaging interval.

83. As the pinion gear reaches its normal ring-gear-enfurther pinion shifting movement of the lever assembly 88 brings the gears into driving engagement and results in opening of the pilot valve 77. This opening of the pilot valve permits the metering of pressurized fluid from the valve inlet chamber 65 to the outlet chamber 50. When the gears are in proper engagement, the pressure initially supplied to the inlet port of the motor through the pilot valve normally is insuicient to effect rotation of the loaded motor. However, when the uid pressure in the valve outlet chamber 50 reaches a predetermined value, this pressure acting on the end of the valve spindle 67 overcomes the combined biasing action of the spring 73 and of the valve inlet pressure as applied to the shoulders 72 and 72 through the grooves 71 and causes the main valve to be shifted to its full-opened position in which the shoulder 72 on the valve spindle abuts the cover plate boss 69. The pressurized fluid thus supplied enters the cylinder bores 30 through the ports 31 and 33 and forces the pistons 36 against the cam ring 38 thereby causing the rotation of the cylinder barrel 29, the drive shaft 26 and, consequently, of the pinion gear 101. As each piston completes its outward stroke, the corresponding ports 31 and 33 are brought into communication with the arcuate outlet port 43; and as the cylinder barrel is further rotated, the cam ring 37 urges the piston inwardly of its bore thereby displacing the fluid in the cylinder bore through the outlet port to the fluid reservoir.

If end abutment of the gear teeth prevents engagement of the pinion and ring gears, further actuating movement of the lever assembly 88 compresses the pinion-biasing spring 100 until the spring has been fully collapsed. This further actuating movement of the lever assembly 88 causes the pilot valve to open, metering pressurized iluid to the valve outlet chamber. The fluid thus metered produces a relatively slow rotation of the relatively unloaded motor until the teeth of the pinion and the ring gear are rotated into alignment for engagement. When the gears are thus aligned, the spring 100 urges the pinion into mesh with the ring gear thereby loading the motor, and further shifting of the pinion and of the pilot valve to their starting-drive positions will be effected by the actuating force which will normally be continuously applied to the control lever assembly during the gear After the gears have been engaged, the load of the engine prevents further rotation of the motor and, as a result, the pressure in the outlet chamber builds up to the predetermined value at which it effects the opening of the main valve 67.

After the engine has been started, the ring gear will attempt to drive the pinion. However, the drag of the hydraulic motor causes the overrunning clutch to overrun thereby unloading the motor. lf the unloaded motor were permitted to remain in full communication with the pressure source, the motor would overspeed and rapidly bleed the pressure source. Such overspeeding would also result in detrimental separations between the pistons and the cam race and excessive heating of the several components of the motor. However, this unloading of the motor also results in a substantial pressure drop in the valve outlet chamber 50 due to throttling across the main valve and the reduced pressure demands of the motor. This pressure reduction in the outlet chamber is suicient to allow the spring 73 and the valve inlet pressure, as applied to the shoulders 72 and 72', to seat the main valve. This movement of the main valve spindle into engagement with the valve seat 64 is visible to the operator and indicates that the engine has been successfully started. Upon observing such valve movement, the operator can release the handle 91 whereupon the lbiasing action of the spring rotates the pilot valve actuating lever in a counterclockwise direction; such rotation causing the actuating lever 83 to carry the pilot valve 77 to its closed position and to rotate the starter drive actuating lever assembly 88 in a clockwise piniondisengaging direction.

While the preferred embodiment of the invention shown in Figures 1 and 2 discloses the combined use of both the fluid* pressure bearings 28 and the O-ring sealed secondary valve` plate 32 to prevent `and accommodate cooking of the cylinder barrel relative to its normal axis of rotation, it is also contemplated that these features of the invention maybe used separately of each other in certain applications depending on the normal operative conditions of the motor.

In the embodiment of the invention shown in Figure 5, a secondary valve plate 132 is interposed between the valve plate 14 and the cylinder lbarrel 29. The valve plate 132 is similar to the previously described secondary valve plate 32 utilized in the embodiment of Figures 1 and 2 but is nonrotatably carried by the main valve plate 14 rather than by the cylinder barrel. The valve plate 132 is sealed with respect to the main valve plate 14 by resilient seals 134 embracing the arcuate port openings 42 and 43. Unlike the previously described embodiment, the cylinder barrel is unsupported relative to the cylindrical housing member 13 and the spring 35 interposed 'between the cylinder barrel and the drive shaft is of a rate suiicient to prevent substantial cooking of the cylinder barrel only at normal operating speeds and torque. Under low-speed, high-torque -operative conditions where the rate of the spring 35 is insuflicient to fully prevent cooking of the cylinder "barrel, the biasing action of the resilient seals interposed between the valve plates maintains the secondary valve plate 132 in sealing engagement with the cylinder barrel thereby preventing detrimental leakage which would otherwise occur under such motor operative conditions.

In the form of the invention shown in Figure 6, the action of the iiuid pressure bearings 28 to prevent any substantial cooking of the cylinder barrel with respect to its normal rotative axis is relied upon to prevent excessive leakage between the mating surfaces of the valve plate and the cylinder barrel under normal motor operative conditions, thereby eliminating the need for a secondary valve plate. It is also contemplated that the bearing 28 may be provided with more than three equi-angularly spaced pressure supply grooves 52, as previously described, to amplify the anti-cooking action of supplied fluid pressure in certain motor applications. ln this embodiment of the invention, the drive shaft 26 may be terminated adjacent the cam plate end of the cylinder barrel, as shown; the loads imposed on the motor end of the shaft being carried by the iiuid pressure bearings 28. This construction permits the elimination of the shaftsupporting ball bearing assembly 27 and its support member 12. In this form of the invention, an imperforate cam `bearing support member 140 may also replace the end cap, as shown;the member 146 being suitably keyed to the cylindrical housing memlber by a set screw 122 and retained therein by a snap ring 121.

While several -embodiments of the invention have been shown and described for the purposes of illustration, it will be appreciated by those skilled inthe art that various modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.

I claim:

l. A hydraulic engine-starting device comprising a housing, a hydraulic motor, la shaft rotatably supported by said housing and drivingly connected to said motor, passage means in said housing through which pressureized fluid is adapted to be delivered to and discharged from said motor to effect rotation of said shaft, a starter drive mechanism including a pinion gear slidably mounted on said shaft and adapted to be rotated therewith, said pinion gear being adapted to engage an enginedriven gear axially spaced from said pinion gear upon sliding movement of said starter drive mechanism on said shaft, a valve assembly for controlling the delivery of pressurized uid to saidmotor, said valve assemblyin- 10 cluding a valve body having an inlet chamber therein adapted to communicate withy a source of hydraulicpresl-sure fluid Vand an outlet chamber communicating with the pressurized-fluid-delivering passage means in said housing, a pilotvalve adapted upon movement'into one positionto establish a limited connection for metering fluid between said inlet and outlet `chambers and into another position to prevent the flow of iluid therebetween, and a main valve adapted to be operable to an open position interconnecting said inlet and outlet chambers by the fluid pressure in said outlet chamber in excess of a preetermined amount, and means biasing said main valve to a closed position preventing the flow of uid between said inlet and outlet chambers when the fluid pressure in said outlet chamber is less than said predetermined amount, and lever means for sliding said starter drive mechanism on said shaft thereby moving said pinion gear toward drivingengagement with said engine-driven gear and for shifting said pilot valve member to vestablish said limited fluid connection between said inlet and outlet chambers as said pinion gear approaches engagement i with said engine-driven gear.

2. In an-engine-starting device including a housing, a vhydraulic motor, a shaft rotatably supported by said housing and drivingly connected to said motor, passage means in said housing through which pressurized uid v is adapted to be delivered to and discharged from said -motor to effect rotation of said shaft, a starter drive mechanism including a pinion gear slidably mounted on `=ment with said engine-driven gear; a valve assembly for CTt controlling the delivery of pressurized fluid to said motor, said valve assembly including a valve body having an inlet chamber adapted to communicate with a source of hydraulic pressure iiuid and an outlet chamber communicating'with the pressurized-fluid-delivering passage means in said housing, a pilot valve adapted upon movement into one position to establish a limited connection for metering iiuid between said inlet and outlet chambers and into another position to prevent the ow of fluid therebetween, and a main valve adapted to be actuated t to an open position interconnecting said inlet and outlet chambers by `the `fluid pressure in said outlet chamber inexcess of a predetermined amount, means biasing said main valve to a closed position preventing the flow of uid between saidV inlet and said outlet chambers whenever said pinion is disengaged from said enginedriven gear whereby the fluid pressure in said outlet chamber is reduced rbelow said predetermined amount, and asecondary lever means responsive to the shifting of said pinion gear toward driving engagement with said engine-driven gear and adapted to move'said pilot valve 'member to establish said limited fluid connection between meansthrough which pressurized iiuid is adapted to be delivered to and discharged from said motor to effect the rotation thereof, a starter drive mechanism including a pinion gear adapted to drivingly engage an enginedriven gear, coupling means energizable to establish a driving connection between said shaft and said pinion,

and means for energizing said coupling means, and a valve assembly for controlling the delivery of pressurized fluid to said motor, said valve assembly including a valve body having an inlet chamber adapted to communicate with a source of hydraulic pressure Huid and an outlet 11 chamber communicating with the pressurized-huiddelivering passage means, a pilot valve adapted upon movement into one position to establish a connection for metering uid between said inlet and outlet chambers and into another position to prevent the iiow of uid therebetween, and a main valve adapted to tbe actuated to an open position interconnecting said inlet and outlet chambers by the uid pressure in said outlet chamber in excess of a predetermined amount, means biasing said main valve to a closed position preventing the flow of fluid between said inlet and outlet cham ers when said coupling is de-energized thereby unloading said motor, and a lever having a lost-motion connection with said pilot valve and an operative connection with said coupling-energizing means whereby said pilot valve member is actuated to establish said metering connection between said inlet and outlet chambers in response to movement of said means tending to energize said coupling.

4. An engine-starting device including a rotary hydraulic motor and a drive mechanism adapted to be driven by said motor, said motor including a shaft, a cylinder barrel having a driving connection with said shaft, said cylinder barrel having a plurality of bores extending longitudinally thereof and terminating adjacent one end thereof in ports of a reduced dimension, the axes of said bores and ports being spaced from and parallel to the axis of said shaft, a valve plate carried by one end of said cylinder and having ports aligned with the ports in said cylinder barrel, a plurality of resilient O-ring seals interposed between said valve plate and said cylinder barrel, each of said seals being concentric with and embracing aligned ports in said barrel and said plate, a stationary member having passages therein terminating in valve ports through which pressurized fluid is adapted to be sequentially delivered to and discharged from said bores upon rotation of said cylinder barrel, means biasing said cylinder barrel toward said valve ports thereby compressing said seals and urging said valve plate into fluid-sealing engagement with the stationary member adjacent said valve ports, piston means reciprocably mounted in said cylinder bores and projecting outwardly therefrom, the outwardly projecting ends of said pistons being in thrust engagement with a cam member rotatably mounted about an axis angularly disposed to and intersecting the axis of rotation of the cylinder barrel, the cooperative action of said cam member and the uid pressure delivered to said bores being operable on said pistons to elect the rotation of said cylinder barrel, said starter drive mechanism including a pinion gear slidably mounted on said shaft within said second chamber and adapted to be rotated therewith, said pinion gear being adapted to engage an engine-driven gear axially spaced from said pinion gear upon sliding movement of said starter drive mechanism on said shaft and, valve means including a valve body having an inlet chamber adapted to communicate with a source of hydraulic pressure fluid and an outlet chamber communicating with the pressurized-fluid-delivering passage in said stationary member, a pilot valve adapted upon movement into one position to establish a connection for metering pressurized uid between said inlet and outlet chambers and into another position to prevent the ow of iluid therebetween, a main valve adapted to be operable by the iluid pressure in said outlet chamber in excess of a predetermined amount to a full-open position interconnecting said inlet and outlet chambers, and means biasing said main valve to a closed position preventing the flow of iiuid between said inlet and said outlet chambers whenever said pinion is disengaged from said enginedriven gear whereby the fluid pressure in said outlet chamber is reduced below said predetermined amount, and means adapted to slide said starter drive mechanism on said shaft therebypmoving said pinion gear toward driving engagement with said engine-driven gear, said last-mentioned means being adapted upon movement in a driving-engagement-establishing direction to shift said pilot valve member to its position establishing said limited fluid connection between said inlet and outlet chambers irrespective of the establishment of said driving connection between said pinion and said engine-driven gears.

5. An actuating mechanism comprising a rotary iluid motor and a drive mechanism, a rotatably supported drive shaft common to said motor and said drive mechanism, said iluid motor including a cylinder member drivingly connected to said shaft, said cylinder member having a plurality of bores therein, said bores terminating adjacent one end thereof in ports of a reduced dimension opening to one end of the cylinder member, a stationary member having an end surface parallel to the port end of saidl cylinder member and having fluid passages therein terminating in ports opening on said end surface through which pressurized fluid is adapted to be sequentially delivered to and discharged from said bores upon rotation of said cylinder barrel, a valve plate carried by one of said members and having ports formed therein in cooperative alignment With the ports in said one member, resilient O-ring seals compressively interposed between said valve plate and said one member, each of said seals spacedly embracing aligned ports in said one member and said plate, means biasing said cylinder barrel axially of said shaft toward said stationary member thereby compressing said seals and urging said valve plate and the other of said members into fluid-sealing engagement; and a piston reciprocably mounted in each of said cylinder bores and projecting outwardly therefrom, the outwardly projecting ends of said pistons being in thrust engagement with a rotatably mounted cam member cooperative with the fluid pressure delivered to said bores to effect the reciprocation of the pistons and the rotation of said cylinder barrel, said drive mechanism including a pinion gear adapted to drivingly engage a driving gear of a load mechanism and coupling means energizable to establish a driving connection between'said shaft and said pinion; valve means including a valve body having an inlet chamber adapted to communicate with a source of hydraulic pressure iluid and an outlet chamber cornmunicating with the pressurized-lluid-delivering passage in said intermediate housing portion, a pilot valve adapted upon movement into one position to establish a limited connection for metering pressurized fluid between said inlet and outlet chambers and into another position to prevent the flow of fluid therebetween, a main valve adapted to be operable to an open position interconnecting said inlet and outlet chambers by fluid pressure in said outlet chamber in excess of a predetermined amount, and means for shifting said pilot valve member to establish said limited fluid connection between said inlet and outlet chambers and energizing said coupling to establish a driving connection between said pinion gear and said shaft.

6. A hydraulic engine-starting device comprising a housing having a lirst chamber adapted to house a hydraulic motor and a second chamber adapted to house a starter drive mechanism, a shaft rotatably supported by said housing and common to said motor and said drive mechanism chambers; said motor including a cylinder barrel having a slidable driving connection with said shaft within said rst chamber, said cylinder barrel having a plurality of bores extending longitudinally thereof, valve means including a member adjacent the port end of said cylinder barrel and having lluid ports therein through which pressurized fluid is adapted to be sequentially delivered to and discharged from said bores upon rotation of said cylinder barrel, means biasing said cylinder barrel axially of said shaft toward said member thereby urging said cylinder barrel into Huid-sealing engagement with said member adjacent said ports, a plurality of pistons reciprocably mounted in said cylinder bores and projecting outwardly therefrom, the outwardly projecting ends of said pistons being in thrust engagement with a cam member rotatably mounted within said lirst chamber about an axis angularly disposed to and intersecting the axis of rotation of the cylinder barrel, the cooperative action of said cam member and the uid pressure delivered to said bores being operable to effect the reciprocation of said pistons and thereby the rotation of said cylinder barrel, and means rotatably journaling said cylinder barrel in said rst chamber and restraining said cylinder barrel from angular and lateral displacement relative to its normal axis of rotation, said means including longitudinally spaced bearings carried by said housing adjacent each end of said cylinder barrel, each of said bearings having a plurality of equi-angularly spaced lluid supply ports therein, and uid passages in said housing interconnecting said bearing ports with the pressurized fluid-delivering port in said member; said starter drive mechanism including a pinion gear slidably mounted on said shaft Within said second chamber and adapted to be rotated therewith, said pinion gear being adapted to engage an engine-driven gear axially spaced therefrom upon sliding movement of said starter drive mechanism on said shaft; valve means including an inlet chamber adapted to communicate with a source of hydraulic pressure iluid, an outlet chamber communicating with the pressurized-uid-delivering port in said member, a pilot valve adapted upon movement into one position to establish a limited connection metering pressurized fluid from said inlet chamber to said outlet chamber and into another position to prevent the ow of fluid therebetween, and a main valve operable by iluid pressure in said outlet chamber in excess of a predetermined amount to an open position interconnecting said inlet and outlet chambers, and means for biasing said main valve to a closed position preventing the llow of fluid between said inlet and said outlet chambers when the lluid pressure in said outlet chamber is less than said predetermined amount; and lever means for shifting said pilot valve member to establish said limited lluid connection between said inlet and outlet chambers and for sliding said drive mechanism `on said shaft to establish driving engagement between said pinion and said engine-driven gear.

7. A rotary actuating mechanism comprising, in combination, a housing; a shaft rotatably supported by said housing; a iluid motor including a cylinder barrel having a driving connection with said shaft; bearing means rotatably journaling said cylinder barrel within said housing, said bearing means including at least two bearing surfaces spaced longitudinally of the cylinder barrel and each of said surfaces having at least three circumferentially spaced pressurized iluid supply ports, said cylinder barrel having a plurality of bores terminating in ports opening on one end of said cylinder barrel, a portion of said housing having fluid passages through which pressurized fluid is adapted to be supplied to said bearing ports and sequentially delivered to and discharged from said bores upon rotation of said cylinder barrel, means biasing said cylinder barrel toward said housing portion thereby urging said cylinder barrel into fluid-sealing engagement with said housing portion, pistons reciprocably mounted in said cylinder bores and projecting outwardly therefrom, the loutwardly projecting ends of said pistons being in thrust engagement with a cam member rotatably mounted within said housing, the axis of rotation of said cam member being angularly disposed to and intersecting the axis of rotation of the cylinder barrel, and the cooperative action of said cam member and the lluid pressure delivered to said bores being operable on said pistons to effect the reciprocation of said pistons and thereby the rotation of said cylinder barrel; a drive mechanism including a pinion gear adapted to drivingly engage a gear adapted to drive a load mechanism, coupling means energizable to establish a driving connection between said shaft and said pinion, and means for energizing said coupling means; valve means including a valve body having an inlet chamber adapted to communicate with a source of pressurized iluid and an outlet chamber communicating with the pressurized-lluid-delivering passage in said intermediate housing portion, a pilot valve adapted upon movement into one position to establish a connection for metering pressurized fluid between said inlet and outlet chambers and into another position to prevent the flow of fluid therebetween, a main valve operable to an open position interconnecting said inlet and Eoutlet chambers by a predetermined fluid pressure, said outlet chamber means biasing said main valve to a closed position preventing the ow of fluid between said inlet and outlet chambers whenever said coupling is de-energized, and a lever having a lost-motion connection with said pilot valve and an operative connection with said coupling-energizing means whereby said pilot valve member is actuated to establish said duid-metering connection between said inlet and outlet chambers in response to movement of said means tending to energize said coupling.

8. An engine-starting device comprising a housing having a first chamber adapted to house a fluid motor and a second chamber adapted to house a starter drive mechanism, a shaft rotatably supported by said housing and common to said motor and'said drive mechanism chambers; a l'luid motor in said first chamber including a cylinder barrel having a slidable driving connection with said shaft within said rst chamber, said cylinder barrel having a plurality of bores extending longitudinally thereof, the axes of said bores being spaced from and parallel to the axis of said shaft, a valve plate carried by one end of said cylinder and having ports aligned with said lbores, a plurality of resilient O-ring seals interposed between said valve plate and said cylinder barrel, each of said seals being concentric with and embracing one of said ports, a portion of said housing intermediate said chambers having fluid passages through which pressurized fluid is adapted to be sequentially delivered to and discharged from said bores through said ports upon rotation of said cylinder barrel, means biasing said cylinder barrel axially of said shaft toward said intermediate housing portion thereby urging said valve plate into fluid-sealing engagement with said intermediate housing portion, a piston reciprocably mounted in each of said cylinder bores and projecting outwardly therefrom, the outwardly projecting ends of said pistons being in thrust engagement with a cam member rotatably mounted Within said lirst chamber remotely from said intermediate housing portion, the axis of rotation of said cam member being angularly disposed to and intersecting the axis of rotation of the cylinder barrel substantially at a point in the plane of engagement between said cam member and said pistons, the cooperative action of said cam member and the fluid pressure delivered to said bores being operable on said pistons to effect the rotation of said cylinder barrel, and means rotatably journaling said cylinder barrel in said first chambenand restraining said cylinder barrel from movement relative to its mounting on said shaft except longitudinally thereof, said means including longitudinally spaced bearings carried by said housing adjacent each end of said cylinder barrel and each of said bearings having a plurality of equiangularly spaced fluid supply ports therein, fluid passages in said housing interconnecting said bearing ports with the pressurized-huid-delivering passage in said intermediate housing portion; a starter drive mechanism in said second chamber including a pinion gear slidably mounted on said shaft within said second chamber and adapted to 'be rotated therewith, said pinion gear being adapted to engage an engine-driven gear axially spaced from said pinion gear upon sliding movement of saidstarter drive mechanism on said shaft; valve means including a valve body having an inlet chamber adapted to communicate with a source of hydraulic pressure iluid and an outlet chamber communicating with the vpressurized-iluid-delivering passage in said intermediate housing portion, a pilot valve adapted upon movement into one position to establish a limited uid convalve member to establish said limited fluid connection between said inlet and outlet chambers.

9. An actuating mechanism comprising a housing having a first chamber adapted to house a uid motor and a second chamber adapted to house a drive mechanism, a shaft rotatably supported 'by said housing and common to said motor and said drive mechanism; a fluid motor in said first chamber including a cylinder barrel having a driving connection with said shaft Within said first chamber, said cylinder barrel having a plurality of bores extending longitudinally thereof and terminating adjacent one end thereof in ports of a reduced dimension, a valve plate carried by the port end of said cylinder barrel and having a plurality of ports formed therein, each of said valve plate ports being in cooperative alignment with one of said cylinder barrel ports, a plurality of resilient O-ring seals compressively interposed between said valve plate and said cylinder barrel, each of said seals being concentric with and embracing aligned ports in said cylinder barrel and said plate, a portion of said housing defining the end of said first chamber adjacent said valve plate and having fluid passages therein through which pressurized uid is adapted to be sequentially delivered to and discharged from said bores through said ports upon rotation of said cylinder barrel, means 'biasing said cylinder barrel axially of said shaft toward said housing portion thereby compressing said seals and urging said valve plate into fluid-sealing engagement withsaid housing portion, a piston reciprocably mounted ineach of said cylinder bores and projecting outwardly therefrom, the outwardly projecting ends of said pistons being in thrust engagement with a cam member rotatably mounted within said first chamber opposite said housing portion about an axis angularly disposed to and intersecting the axis of rotation of the cylinder barrel, the cooperative action of said cam member and the uid pressure delivered to said bores being operable on said pistons to effect the rotation of said cylinder barrel, and bearing means rotatably journaling said cylinder barrel in said first chamber, said bearing means including at least two bearing surfaces spaced longitudinally of said cylinder barrel, each of said bearing surfaces having at least three equi-angularly spaced lluid supply ports therein, fluid passages in said housing interconnecting said bearing ports with the pressurized-lluid-delivering passage in said intermediate housing portion, the pressurized fluid supplied to said bearing r ports being operable on said cylinder barrel to limit the movement thereof relative to its normal axis of rotation; a drive mechanism in said second chamber including a pinion gear adapted to drivingly engage a driving gear of a load mechanism and coupling means energizable to establish a driving connection between said shaft and said pinion; valve means including a valve body having an inlet chamber adapted to communicate with a source let chambers when the fluid pressure in said outlet chamber is less than said predetermined amount, and means for shifting said pilot.valve member to establish said limited fluid connection between said inlet and outlet chambers and energizing said coupling to establish a driving connection between said pinion gear and said shaft.

l0. A hydraulic engine-starting device comprising, in combination, a housing, a shaft rotatably supported by said housing, a hydraulic motor including a cylinder barrel having a slidable driving connection with said shaft, bearing means journaling said cylinder barrel within said housing, said bearing means including axially and circumferentially spaced fluid pressure supply means adapted to limit angular and lateral displacement of said cylinder barrel relative to its normal axis of rotation, said cylinder barrel having a plurality of bores extending longitudinally thereof and terminating adjacent one end thereof in ports of reduced dimension, a valve plate carried by the port end of said cylinder barrel and having ports therein aligned with the ports in said cylinder barrel, a plurality of resilient O-ring seals interposed between said valve plate and said cylinder barrel, each of said Seals being concentric with and embracing aligned ports in said barrel and said plate, a portion of said housing having fluid passages through which pressurized fluid is adapted to be sequentially delivered to and discharged from said bores through said ports upon rotation of said cylinder barrel, means biasing said cylinder barrel axially of said shaft toward said housing portion thereby compressing said seals and urging said valve plate into fluid-sealing engagement with said housing portion, a piston reciprocably mounted in each of said cylinder bores and projecting outwardly therefrom, the outwardly projecting ends of said pistons being in thrust engagement with a cam member rotatably mounted Within said housing about an axis angularly disposed to and intersecting the axis of rotation of the cylinder barrel, the cooperative action of said cam member and the fluid pressure delivered to said bores being operable on said pistons to effect the rotation of said cylinder barrel, a starter drive mechanism including a pinion gear slidably mounted on said shaft and adapted to be rotated therewith, said pinion gear being adapted to engage an enginedriven gear normally axially spaced from said pinion gear upon sliding movement of said starter drive mechanism on said shaft, valve means including a valve body having an inlet chamber adapted to communicate with a source of hydraulic pressure fluid and an outlet chamber communicating with the pressurized-lluid-delivering passage in said intermediate housing portion, a pilot valve adapted upon movement into one position to establish a limited connection for metering pressurized lluid between said inlet and outlet chambers and into another position to prevent the flow of fluid therebetween, a main valve adapted to be operable to an open position interconnecting said inlet and outlet chambers by the fluid pressure in said outlet chamber in excess of a predetermined amount, and means biasing said main Valve to a closed position preventing the flow of lluid between said inlet and said outlet chambers whenever said pinion is disengaged from said engine-driven gear whereby the fluid pressure in said outlet chamber is reduced below said of hydraulic pressure fluid and an outlet chamber compredetermined amount, and means adapted to slide said starter drive mechanism on said shaft thereby moving said pinion gear toward driving engagement with said engine-driven gear and to shift said pilot valve member to its position establishing said limited fluid connection between said inlet and outlet chambers irrespective of the establishment of said driving connection between said pinion and said engine-driven gears.

1l. A rotary fluid motor including a rotatably supported drive shaft, a cylinder member having a driving connection with said shaft, said cylinder member having a plurality' of bores therein, said bores terminating ad- 17 y jacent one end thereof in ports of a reduced dimension opening to one end of the cylinder member, a stationary member having an end surface parallel to the port end of said cylinder member and having'fluid passages therein terminating in ports opening on said end surface through which pressurized fluid is adapted to be sequentially delivered to and discharged from said bores upon rotation of said cylinder member, a valve plate interposed between and carried -by one of said members, said valve plate having a plurality of ports formed therein in cooperative alignment with the ports in said one member, resilient O-ring seals compressively interposed between said valve plate land said one member, each of said seals spacedly embracing the aligned ports in said one member and said plate, means biasing said cylinder barrel axially of said shaft toward said stationary member thereby compressing said seals and urging said valve pl-ate and the other of said members into rotative fluid-sealing engagement, and a plurality of pistons reciprocably mounted in said cylinder bores and projecting outwardly therefrom, the outwardly projecting ends of said pistons being in thrust engagement with a rotatably mounted cam member cooperative with the fluid pressure delivered to said bores to effect the reciprocation of said pistons and the rotation of said cylinder barrel.

12. A hydraulic motor comprising, in combination, a housing, a cylinder barrel rotatably supported in said housing, said cylinder barrel having a plurality of bores extending longitudinally thereof and terminating adjacent one end thereof in ports of reduced dimension, a valve plate carried by the port end `of said cylinder barrel and having ports therein laligned with the ports in said cylinder barrel, a plurality -of resilient O-ring seals interposed between said valve plate and said cylinder barrel, each of said seals being concentric with and embracing -aligned ports in said barrel and said plate, a portion `of said housing having fluid passages through which pressurized fluid is adapted to be sequentially delivered to and discharged from said bores through said ports upon rotation of said cylinder barrel, means biasing said cylinder barrel toward said housing portion thereby compressing said seals and urging said valve plate into fluidsealing engagement with said housing portion, and a piston reciprocably mounted in each of said cylinder bores and projecting outwardly therefrom, the outwardly projecting ends of said pistons being maintained in thrust engagement with a cam member by the pressurized fluid supplied to said bores, the cooperative action of said cam member and the fluid pressure delivered to said bores being operable on said pistons to effect the rotation of said cylinder barrel.

13. A rotary hydraulic motor including a housing, a shaft rotatably supported by said housing, a cylinder barrel having a driving connection with said shaft, said cylinder barrel having a plurality of bores therein termihating adjacent one end thereof in ports of reduced dimension, a portion of said housing having fluid passages through which pressurized fluid is adapted to be sequentially delivered to and discharged from said bores through said ports upon rotation of said cylinder barrel, means biasing said cylinder barrel into fluid-sealing engagement with said housing portion, a piston reciprocably mounted in each of said cylinder bores and projecting outwardly therefrom, the outwardly projecting ends of said pistons being in thrust engagement with a cam member cooperative with the fluid pressure delivered` to said bores to effect the reciprocation of said pistons and thereby the rotation of said cylinder barrel, and bearing means journaling said cylinder barrel within said housing, said bearing means including a plurality of axially and circumferentially spaced fluid pressure supply ports connectable to a source of fluid pressure, the pressurized' fluid supplied to said ports from said source being operable to limit angular and lateral displacement of said cylinder barrel relative to its normal axis of rotation.

14. In a rotary cylinder fluid motor, the combination comprising a housing, a cylinder barrel having a plurality of bores extending longitudinally thereof and terminating adjacent one end thereof in ports of a reduced dimension, bearing means rotatably journaling said cylinder barrel within said housing chamber and restraining said cylinder barrel from movement relative to its mounting on said shaft except longitudinally thereof, said bearing means including at least two bearing surfaces spaced longitudinally of said housing and adjacent each end of said cylinder barrel, each of said bearing surfaces having at least three equi-angularly spaced fluid supply ports opening thereon, said housing having fluid passages therein adapted to supply pressurized fluid to said bearing ports and having ports adjacent the port end of said barrel adapted to sequentially deliver and discharge pressurized fluid to and from said bores through said ports upon rotation of said cylinder barrel, means biasing said cylinder barrel into fluid-sealing engagement with the surfaces of said housing adjacent said housing ports, pistons reciprocably mounted in said cylinder bores and projecting outwardly therefrom into thrust engagement with a cam member rotatably mounted within said housing chamber, the axis of rotation of said cam member being angularly disposed to and intersecting the axis of rotation of the cylinder barrel, and the cooperative action of said cam member and the iluid pressure delivered to said bores being operable on said pistons to effect the reciprocation of said pistons and the rotation of said cylinder barrel.

15. In a fluid motor, the combination comprising a housing having a chamber therein, a shaft rotatably supported by said housing, said motor including a cylinder barrel having a driving connection with said shaft within said chamber, said cylinder barrel having a plurality of bores extending longitudinally thereof and terminating adjacent one end thereof in ports of a reduced dimension, a valve plate carried by the port end of said cylinder barrel and having a plurality of ports formed therein, each of said valve plate ports being in cooperative alignment with one of said cylinder barrel ports, a plurality of resilient O-ring seals compressively interposed between said valve plate and said cylinder barrel, each of said seals being concentric with and embracing aligned ports in said cylinder barrel and said plate, a portion of said housing defining the end of said chamber adjacent said valve plate having fluid passages therein through which pressurized fluid is adapted to be sequentially delivered to and discharged from said bores through said ports upon rotation of said cylinder barrel, means biasing said cylinder barrel axially of said shaft toward said housing portion thereby compressing said seals and urging said Valve plate into fluid-sealing engagement with said housing portion, a piston reciprocably mounted in each of said cylinder bores and projecting outwardly therefrom, the outwardly projecting ends of said pistons being in thrust engagement with a cam member rotatably mounted within said chamber opposite said end portion about an axis angularly disposed to and intersecting the axis of rotation of the cylinder barrel, the cooperative action of said cam member and the fluid pressure delivered to said bores being operable on said pistons to effect the rotation of said cylinder barrel, and bearing means rotatably journaling said cylinder barrel in said housing chamber, said bearing means including -two axially spaced annular bearings mounted in said housing adjacent each end of said cylinder barrel, each of said annular bearings having at least three equi-angularly spaced ports therein, and means for supplying pressurized luid to each of said bearing ports, the pressurized iluid supplied to said bearing ports being operable on said cylinder to limit angular and lateral displacement of said cylinder barrel relative to its normal axis of rotation.

16. In a fluid motor, a rotating member having a plurality of ports therein opening on one surface thereof, a

stationary member having a surface thereon in spaced relation to said rotating surface and having ports therein opening on said stationary surface and adapted to'be sequentially aligned with said first-mentioned ports upon rotation of the rotating member, a third member interposed between said rotating and said stationary members, said third member being non-rotatably secured to one of said members and having a plurality of ports therein in cooperative alignment with the ports in said one member, and resilient sealing means compressively interposed between said valve member and said one member and adapted to seal the aligned ports in said one member and said third member and to bias said third member into rotative fluid-sealing engagement with the other of said members.

17. The combination as set forth in claim 16 and including bearing means rotatably journaling said rotating member, said bearing means being adapted to restrain said rotating member from transverse and angular movement relative to said stationary member and including at least two bearing surfaces spaced longitudinally of the rotative axis of said rotating member and each of said bearing surfaces having at least three equi-angularly spaced uid supply ports opening thereon, and means for supplying pressurized fluid to said bearing surface ports.

18. In a fluid motor including a housing and a cylinder member adapted to be rotatably supported therein, bearing means journaling said cylinder member within said housing and including a plurality of axially and circumferentially spaced fluid pressure supply ports, said ports being connectable to a source of fluid pressure and the fluid pressure supplied thereto from said source being adapted to limit angular and lateral displacement of the cylinder member relative to its normal axis of rotation.

19. In a fluid motor, a cylinder member, and bearing means rotatably journaling said cylinder member, said bearing means being adapted to restrain said cylinder member from transverse and angular movement relative to its normal rotative axis yand including at least two bearing' surfaces spaced longitudinally of said cylinder member and each of said bearing surfaces having at least threeequi-angularly spaced fluid supply ports opening thereon adapted to be connected to a supply of pressurized fluid.

20. In a power-transmitting mechanism comprising a fluid actuated motor and a drive mechanism adapted to selectively couple the motor to a load device, a valve assembly for controlling the delivery of pressurized fluid to the motor, said valve assembly including a pilot valve adapted upon movement into one position to meter pressurized fluid to said motor, a main valve adapted to be actuated to an open position when the fluid supplied to said motor by said pilot valve reaches a predetermined pressure, and means operable in response to fluid pressure supplied to said motor to bias said main valve to a closed position thereby preventing the flow of pressurized uid therethrough whenever the fluid pressure supplied to said motor is less than said predetermined amount, and said pilot and main valves being ineffective to supply pressurized fluid in excess of said predetermined pressure unless said motor is coupled to said load device by said drive mechanism.

References Cited in the file of this patent UNITED STATES PATENTS Born Feb. 2l, 

